After years of stopgap road-building projects to ease its worst traffic tie-ups, Fairfax County officials have recommended a $134.4 million road bond issue, which, ifpassed at referendum this fall, would represent the largest sum ever borrowed by a locality to build roads in Virginia.

Yet despite the size of the proposed bond package -- and the fact that it would include about $90 million to build two segments of the long-awaited cross-county Springfield Bypass -- Fairfax officials acknowledge it is a small step given the scope of the county's transportation needs.

"It's a drop in the bucket compared to what's needed in this county," said Supervisor Audrey Moore, a Democrat.

County Executive J. Hamilton Lambert was a little more generous in his assessment. "It's filling the bucket one-quarter of the way."

Lambert himself has called the proposed bond referendum "historic." If passed by county voters Nov. 5, it would provide the first funds to build segments of the Springfield Bypass, which has been touted by politicians for more than a decade as a panacea for county traffic woes.

The proposed referendum also marks a milestone in a process that began in 1981, when the Virginia General Assembly for the first time allowed large counties such as Fairfax to borrow money to finance road improvements. Until that move, road building had been considered an exclusive responsibility of the state since the Depression.

After that legislation, county voters overwhelmingly approved road bond issues of $30 million in 1981 and $25 million in 1982.

But those amounts were considered by county officials principally as a supplement to annual road funding from the state.

The bond package proposed to the Board of Supervisors this week moves the county closer to replacing the state as the primary source of road construction revenue, county officials say. The county received about $10 million from the state for road construction this fiscal year.

"It's a recognition that the Commonwealth of Virginia is not in a position to provide us with this level of funding," said Lambert.

According to county Transportation Director Shiva K. Pant, the $134.4 million bond would provide the county with three times as much in road-building funds as Fairfax expects from the state during the next six years.

Pointing to the $90 million price to build the first eight miles of the Springfield Bypass, Pant said, "If we didn't go to a bond, there is no way from the state allocation you can ever accumulate that much."

The $90 million would be used to build two key segments of the bypass -- one from the Dulles Toll Road to Rte. 50 in the northwestern section of the county and the other from Rolling Road across I-95 to Beulah Street in the county's southeast.

Private developers also are building some parts of the bypass, such as the stretch between Rte. 50 and I-66 being built by John T. (Til) Hazel and another segment near Franconia that will be financed by Miller & Smith as part of the firm's Kingstowne development.

But even after those privately financed parts of the bypass are factored in, more than 20 miles of the proposed 35-mile bypass will remain to be built. The final cost of the entire road could run to $500 million or more, depending on how soon it is built.

County officials would like to see private developers pick up at least some of the tab of building the rest of the bypass, but they acknowledge that another road bond referendum in the next five to 10 years is probable. Pressures from commuters and developers to complete the bypass and improve roads in fast-growing areas such as the Rte. 28 corridor in the county's western section are unlikely to dissolve, they say.

Politicians such as County Board Chairman John F. Herrity, who has hitched his political career to transportation issues, frequently say it would take $1 billion to pay for all the road projects the county needs.

County officials who drew up the bond package could easily have produced a proposal of $200 million or more, but were constrained by political fears that voters would balk at too large an issue on the fall ballot, and by financial fears that bond-rating companies would withdraw the county's AAA bond rating if it borrowed too much through referenda.

"We have got to keep the pressure on the transportation problem," said Lambert.